Water for the Recovery of the Climate -

A New Water Paradigm

Michal Kravcik, Juraj Kohutiar NGO „People and Water“

Slovakia

Water Tribune, Zaragoza, 23rd August 2008

TOPICS OF THIS PRESENTATION

INTRODUCTION

BODY

• Human impact on water cycle

• Water cycle and climate change

• Recovery of the climate

CONCLUSION

HUMAN IMPACT

ON WATER CYCLE

“On July 22d [1494], he [Columbus] departed for Jamaica…. every afternoon there was a rain squall that lasted for about an hour. The admiral attributes this to the great forests of that land; he knew from experience that formerly this also occurred in the Canary, Madeira, and Azore Islands, but since the removal of forests that once covered those islands they do not have so much mist and rain as before.”

/Christopher Columbus’ biography

by his son Ferdinand/

FRESHWATER STOCKS ON EARTH

DEFORESTATION & AGRICULTURE

Deforestation / some forms of farming cause:

• increase of runoff (and erosion)

• lower infiltration (groundwater recharge)

• lower evaporation (change of regional climate)

• natural meanders removed

• adjacent swamps drained

• shortening length increases slope

• acceleration of runoff • lowering land's ability

to retain water

ALTERATION OF RIVERS

SOIL SEALING IN CITIES

• about 20 billion m3 of rainwater sluiced from municipalities of Europe annually

PAVEMENT IMPACT

• infiltration decreases (groundwater recharge decreases)

• evaporation decreases (air humidity decreases)

• runoff increases (through sewage to rivers and sea)

Free surface

Paved surface

Precipitation

(mm/ year)

Volume of water circulating

Runoff (indicator of soil sealing)

Europe 750 7 790 km3 36 %

Slovakia 762 37 km3 34 %

Prešov, SK (City center)

628 12 mil. m3 72 %

Plot of land 630 0,5 mil. m3 37 %

Residential house

630 766 m3 76 %

WATER BALANCE OF THE INVESTIGATED TERRITORY

RUNOFF FROM URBANAND FOREST ENVIRONMENTS

Decrease of runoff is overlooked flood prevention measure

SOIL SEALING DESTROYSSMALL WATER CYCLE(S) ON LAND

EARTH – WATER BUDGET

Oceans

Atmosphere

Land Evaporation361 000 km³/year

Precipitation324 000

km³/year

Runoff37 000

km³/year

Precipitation99 000

km³/yearEvaporation

62 000

km³/year

There is more water in „small“ water cycle than in „large“ water cycle!!!

WATER CYCLE

AND

CLIMATE CHANGE

The rain in Spain falls

mainly on the plain... (???)

The rain in Slovakia fails mainly on the plain...

HOT CLIMATIC UMBRELLA OF A CITY

Soil sealing resulting in the lack of evapotranspiration in urban areas is the main reason of “urban heat island” effects.

Why the rain fails mainly on the plain?

Rising air flows push precipitation away to colder and more humid areas

PRECIPITATION TRENDS IN CITY PRESOV

PRECIPITATION TRENDS IN SLOVAKIA

PRECIPITATION IN MOUNTAINS AND

LOWLANDS – DANUBE WATERSHED

RECOVERY

OF THE CLIMATE

When fire and water are at war,

it is the fire that loses.   

/Spanish Proverb/

GROWTH OF EXTREME WEATHER WITH

DECLINE OF SMALL WATER CYCLE

The less water “soil sealing” allows in small water cycle, the more frequent and more severe are extremes of weather

DESTRUCTION AND RENEWAL OF SMALL WATER CYCLE

There is a hope of recovery by returning the lost water back to the land.

RAINWATER HARVESTING FROM ROOFS IN CITIES

WATER CYCLE OF A FAMILY HOUSE

RAINWATER HARVESTING ON SLOPES

RAINWATER HARVESTING EXAMPLES

INFRARED PICTURE OF THE „WATER FOREST“

Li1

20.0

33.0 °C

22

24

26

28

30

32

FLI R Syst ems

°C

2021222324252627282930313233

Label Cursor Min Max

Li1 - 19.7 35.9

SUMMARY

Take care, your worship,

those things over there

are not giants

but windmills...

Miguel de Cervantes, Don Quijote

Old water paradigm

• protects surface water as the main source and reserve of water

New water paradigm

• protects groundwater and soil water as the main treasure of water

www.waterparadigm.org

Old water paradigm

• soil sealing has minimal impact on the water cycle

New water paradigm

• soil sealing has a fundamental impact on the water cycle

www.waterparadigm.org

Old water paradigm

• soil sealing has minimal influence on global warming

New water paradigm

• soil sealing may be important factor in global warming

www.waterparadigm.org

Old water paradigm

• rainwater is an inconvenience, needs to be quickly removed

New water paradigm

• rainwater is an asset that needs to be retained (especially in soil/plants)

www.waterparadigm.org

GRACIAS! THANKS!MERCI! DANKE!

ĎAKUJEM!... ... ...